# Keihin SH7054 (Triumph 865 twin, mechanical odo) — table map

Reversed from `Nc()`/`Lb()` in `l.java` and validated against the stock reference
maps. All offsets are in the reconstructed **flat ROM** (0x60000). Compute per map:

```
fe   = c.a[Qd*48]                 # Qd from the s.a directory lookup on the map signature
base = (fe[0] & 0x2F0) << 12      # = 0x50000 for the 865 twin family
offset(table) = base + fe[<field>]
```

Main tables are **32 rows (RPM) × 20 cols (throttle), 16-bit big-endian**.

## Axes

| Axis | fe field | Entries | Values (20187) | Meaning |
|---|---|---|---|---|
| RPM (rows) | `fe[8]` | 32 | 0, 500, 900, 1000 … 10000 | engine speed, direct RPM |
| Throttle (cols) | `fe[27]` | 20 | 0, 10, 20 … 780, 1000 | throttle %, ÷10 (0–100.0%) |

## Tables (validated by production 20187 vs aftermarket 20188 diff)

| Table | fe | Offset (20187) | Value range | Notes |
|---|---|---|---|---|
| Main fuel — cyl 1 | 11 | 0x56990 | 951–10480 | **strong**: 75% diff, smooth VE, aftermarket richer |
| Main fuel — cyl 2 | 12 | 0x56E90 | 951–10680 | **strong**: 67% diff |
| Low-throttle fuel — cyl 1 | 15 | 0x55590 | 0–10760 | 70% diff; starts at 0 (closed throttle) |
| Low-throttle fuel — cyl 2 | 16 | 0x55A90 | 0–10810 | 68% diff; cyl-1 pair |
| Fuel — base/idle | 9 | 0x55500 | 0–10760 | 61% diff; lower values |
| Ignition advance — gear 1 | 19 | 0x587D0 | 13–600 | 4 evenly-spaced (0x500) 20×32 tables |
| Ignition advance — gears 2–5 | 20 | 0x58CD0 | 13–600 | main operating map |
| Ignition advance — gear 6 | 21 | 0x591D0 | 13–600 | overdrive |
| Ignition advance — neutral | 22 | 0x596D0 | 60–600 | idle/free-rev |

## AFR / target lambda

`fe[2]` @ 0x52260 is an interleaved (value, breakpoint) curve where **128 = λ1.00
(stoich, 14.7 AFR)** — e.g. `… 128, 500, 128, 400, 128, 300 …`. The `128` cells are
the closed-loop lambda targets; disabling closed loop (O2 delete) lets you set
these richer. Exact dimensions still being confirmed.

## Scaling (confidence varies)

- **Fuel** values are VE/fuel-mass in the ECU's internal units (≈ 0–10800). Real
  units (injector µs / VE %) need the ECU's fuel constant; relative changes are
  exact, absolute scaling TBD.
- **Ignition** 13–600 is advance in an internal unit (candidate: value ÷ 10 = °BTDC,
  giving ~1.3–60°; the low-RPM row 90→14→20 fits a retard-then-advance curve). TBD.
- **AFR** 128 = λ1.00 is solid (standard Keihin convention).

## SAI / O2 / lambda flags

Now findable via the localised flat-ROM diff (20187 vs 20188), which isolates small
single-byte changes (e.g. 0x50C13, 0x534AD, 0x59759) as prime toggle candidates.
Confirming which is SAI vs O2 needs either bench testing or the finer `Nc` device
logic — a follow-up.

## Status

Fuel and ignition table **locations** are validated end-to-end. Remaining: exact
scaling constants, AFR dimensions, and confirming the individual device flags.